From Hard Drop - Tetris Wiki
JZ/LS stacking is a back-to-back TSD method invented by player Yakine. It is characterized by a repeated JZ or LS pattern creating platforms for the TSD to take place.
 Basic setup
The notch setups on the side are typically done with the LSO pieces (assuming LZ stacking), with the I pieces staying near the back. This is definitely the part that takes the most practice.